Method of producing longitudinal ribs on the exteriors of tubes



A T. E. MURRAY, 1a., AND J. B. MURRAY.

METHOD OF PRODUCING LONGITUDINAL RIBS ON THE EXTERIORS OF TUBES. APPLICATION HLED 056.24. 1919.

1,339,970, Patented 1... 11 1920.

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UNITED STATES PATENT OFFICE.

THOMAS E. MURRAY, JR., AND JOSEPH B. MURRAY, 0F BROOKLYN, NEW YORK.

METHOD OF PRODUCING- LONGITUIDINAL RIBS ON THE EXTERIORS OF TUBES.

Specification of Letters Patent.

Patented May 11, 1920.

Application filed December 24, 1919. Serial No. 347,214.

To all whom it mayconcern Be it known that we, THOMAS E. MURRAY, J r., and J OSEPH B. MURRAY, citizens'of the United States, residing at Brookl n, in the county of Kings and State of ew York, have invented a certain new and useful In provement in Methods of Producin L0ng1- tudinal Ribs on the Exteriors of ubes, of which the following is a specification.

The invention is a method of forming longitudinal ribs on a tube by electrically heating certain portions of said tube, while subjectin said portions to compression to eXtrude t e same outwardly.

In the accompanying drawing Figure 1 is a cross section of the electrodes, the tube therein and the mandrel within the tube before the flanging operation.v Fig. 2 is a similar view, after the flanging operation is completed. Fig. 3 is a perspective view of the tube with the flanges formed thereon. Fig. 4: is a view similar to Fig. 1, showing a tube of modified trodes are to be relatively movable to compress the portions B, C simultaneously.

lVhen the heating current is established and the electrodes E, F are caused to compress the metal of the portions 13, C fused thereby, said metal is prevented from becoming inwardly extruded by the mandrel H, and is, therefore, outwardly extruded to form longitudinal ribs I, J on the tube. The width of the ribs will depend upon the permitted degree of approximation of the opposing faces of the electrodes. The tube may be of any desired cross sectional shapeas, for example, quadrangular, as shown in Fig. 4, the electrodes and mandrel being correspondingly formed.

\Ve claim:

The method of producing longitudinal ribs on the exterior of a tube, which consists in seating the tube in electrodes having a gap between their opposing faces, while internally supporting the portions of said tube bridging said gap, establishing a heating current, and moving said electrodes relatively to one another, whereby the metal of said bridging portions is fused and extruded to form said external ribs.

In testimony whereof we have affixed our signatures in presence of two witnesses.

THOMAS E. MURRAY, JR. JOSEPH B. MURRAY.

Viitnesses GERTRUDE T. PORTER, ll'IAY T. MoUrARRY. 

